PROJECT SUMMARY Interstitial Lung Diseases (ILDs), represent a large group of chronic pulmonary disorders that are common causes of morbidity and mortality of both children and adults worldwide. Alveolar dysfunction, pulmonary fibrosis, and vascular remodeling associated with chronic ILDs lead to progressive respiratory failure for which they are few effective therapies. Both genetic and environmental factors underlie the pathogenesis of ILDs; including smoking, air pollution, and chronic inflammation and genetic disorders. Mutations in genes regulating surfactant homeostasis or alveolar type 2 (AT2) cell function or survival includes ABCA3, SFTPB, SFTPC, SFTPA, Telomerase (and related genes) that cause respiratory failure in neonates, children, and older individuals. Our PCTC Consortium seeks to develop novel strategies designed to use CRISPR/CAS9 gene editing for lung progenitor cells for correction of a prototypic Childhood Interstitial Lung Diseases (CHILD) disorder that disrupts pulmonary surfactant homeostasis (ABCA3 deficiency) that leads to fatal infantile lung disease. Mutations in in the ABCA3 gene disrupts surfactant lipid and protein production gene causing severe respiratory dysfunction after birth or chronic lung disease in infancy. We will apply CRISPR/CAS9 mediated gene editing to correct ABCA3 in alveolar progenitor cells as disease targets applicable to other genetic and acquired disorders affecting AT2 cells and their progenitors. The identification, targeting and gene editing of alveolar AT2 cells and their progenitors will be widely applicable for the treatment of both genetic and acquired diseases of the peripheral lung in the future.